Study On The Antagonistic Effect Of Cashew ACE Inhibitory Peptide On Acute Hepatitis In Mice

Renin angiotensin system(RAS)is an important humoral regulation system in human body.The RAS includes angiotensin converting enzyme(ACE),angiotensin II(Ang II),angiotensin II composition such as type 1 receptor(AT1R).RAS can be activated when the liver is stimulated by alcohol and other pathogenic factors,resulting in impaired liver structure and function.Functional peptide with ACE inhibitory activity(ACE inhibitory peptide)can reduce the damage degree of alcohol to liver by reducing the expression of RAS.Food protein source ACE inhibitory peptide has wide application value due to its wide range of sources,non-toxic side effects and high safety features.Cashew is the most tropical economic crop in Hainan.Cashew is the most tropical economic crop in hainan.Cashew has the inhibitory activity of ACE inhibitory peptides,which provides new ideas for the development of food for the prevention of acute hepatitis.Objective:In this paper,we obtained ACE inhibitory peptide from cashew nut and discussed its antagonistic effect on acute hepatitis in mice induced by ethanol.It can broaden the research approach to prevent acute hepatitis and provide experimental data for the development and utilization of cashews.Methods:Single factor experiments were used to analyze the effect of material-liquid ratio,pH,extraction time,and extraction temperature on the extraction rate of cashew protein.Response surface analysis was used to determine the best extraction conditions.The enzymatic hydrolysis of cashew protein was optimized and purified by dialysis,glucan gel G-25 and RP-HPLC.With the ACE inhibition rate as the evaluation index,the components with the highest ACE inhibition rate were collected.Establish a mouse model of acute hepatitis by histopathological examination,ELISA method,immune histochemical method,Real-Time-PCR method,on the liver pathology,liver function and inflammatory factor levels and ACE-Ang ?-AT1R expression quantity for testing.Results:(1)Determination of isolation and purification conditions of cashew ACE inhibitory peptides.Response surface optimization experiments showed that when the pH was 11,the temperature was 40?,the extraction time was 1.5 h,and the ratio of solid to liquid was 1:40,the highest extraction rate of cashew protein was 87.1 ± 1.05%.After the enzymolysis,dialysis,and multi-step purification,the fraction of P4-3 with the highest ACE inhibition rate was obtained,and the ACE inhibition rate was 91.04±0.31%.(2)The protective effect of cashew ACE inhibitor peptide on mouse liver.High doses of cashew ACE inhibitory peptide(800 mg/kg d)could significantly improve the morphology and arrangement of hepatocytes,lipid content was significantly reduced(p<0.01),serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST)levels were decreased(p<0.01),superoxide dismutase(SOD)and glutathione(GSH)activity increased(p<0.01),malondialdehyde(MDA)levels in liver homogenate decreased(p<0.05),cytokine interleukin-6 The expression of IL-6 and TNF-a was down-regulated(p<0.01),and the expression of ACE,Ang? and AT1R was down-regulated(p<0.01,p<0.05).Conclusion:Cashew ACE inhibitory peptide(800 mg/kg d)had antagonistical effect on liver injury induced by alcohol.It can make liver tissue structure,liver function level,cytokine level and so on become normal,RAS expression is down-regulated.These confirmed that ACE inhibitory peptides reduce liver damage by down-regulating the expression of ACE-Ang-AT1R axis in the liver tissue RAS.